Medical device for modification of left atrial appendage and related systems and methods

ABSTRACT

Several embodiments are set forth of devices, systems and methods for modifying an atrial appendage such as a left atrial appendage (LAA). In one embodiment, a medical device includes a frame member and a tissue growth member. The frame member includes a unitary, seamless central portion having a plurality of struts defining a multi-cellular structure and an anchoring system, the plurality of struts extending between and configured to self-expand and directly bias the anchor system to anchor the frame member at least partially within the LAA. With this arrangement, the tissue growth member is attached to the frame member to occlude the LAA.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 12/253,831, filed Oct. 17, 2008, now U.S. Pat. No.8,845,711, which application claims the benefit of U.S. ProvisionalPatent Application Ser. No. 60/981,451, filed Oct. 19, 2007, entitledMEDICAL DEVICE FOR MODIFICATION OF LEFT ATRIAL APPENDAGE, and of U.S.Provisional Application Ser. No. 61/047,058 filed Apr. 22, 2008 entitledDEVICE AND SYSTEM FOR ANEURYSM EMBOLIZATION, the disclosure of each ofwhich is incorporated by reference herein in their entireties.

TECHNICAL FIELD

The present invention relates generally to the modification of a leftatrial appendage and, more specifically, to devices, systems and methodsfor occluding or otherwise structurally altering such appendages.

BACKGROUND

The left atrial appendage is a feature of all human hearts. The upperchambers of the heart, the atria, have this appendage attached to eachof them. The physiologic function of such appendages is not completelyunderstood, but they do act as a filling reservoir during the normalpumping of the heart. The appendages typically protrude from the atriaand cover an external portion of the atria. Atrial appendages differsubstantially from one to another. For example, one atrial appendage maybe configured as a tapered protrusion while another atrial appendage maybe configured as a re-entrant, sock-like hole. The inner surface of anappendage is conventionally trabeculated with cords of muscular cardiactissue traversing its surface.

The atrial appendages are inert while blood is being pumped through themduring normal heart function. In other words, the appendages don't havea noticeable effect on blood pumped through them during normal heartfunction. However, in cases of atrial fibrillation, when the atria gointo arrhythmia, blood may pool and thrombose inside of the appendages.Among other things, this can pose a stroke risk when it occurs in theleft appendage since the thrombus may be pumped out of the heart andinto the cranial circulation.

Historically, appendages have sometimes been modified surgically toreduce the risk imposed by atrial fibrillation. In recent years deviceswhich may be delivered percutaneously into the left atrial appendagehave been introduced. The basic function of these devices is to excludethe volume within the appendage with an implant which then allows bloodwithin the appendage to safely thrombose and then to be graduallyincorporated into cardiac tissue. This can leave a smooth,endothelialized surface where the appendage used to be.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention include percutaneously deliveredimplants or medical devices designed to exclude or modify the innersurface of the left atrial appendage to reduce the risk of stroke duringatrial fibrillation. Embodiments of the present invention furtherinclude related methods and systems.

In accordance with one embodiment of the present invention, a medicaldevice for modifying a left atrial appendage (LAA) is provided. Themedical device includes a body formed of a self-expanding material. Thebody exhibits a textured surface including a plurality of protrudingportions and a plurality of recesses. Each protruding portion isseparated from an adjacent protruding portion by a recess of theplurality of recesses. In one embodiment, the body may exhibit asubstantially spherical geometry. The body may be formed from a materialthat comprises, for example, a reticulated foam.

In accordance with another embodiment of the present invention, amedical device for modifying a left atrial appendage includes a mesh bagand at least one self-expanding body disposed within the mesh bag. Theself-expanding body may include one or more foam bodies. The mesh bagmay be formed of, for example, a material comprising at least one nylon,polyester or silicone. The self-expanding body or bodies may be formedof, for example, at least one of a polymer foam, polyurethane, andpolyvinyl acetate.

In accordance with another embodiment of the present invention, a methodof modifying a left atrial appendage is provided. The method includesproviding a body formed of a self-expanding material, the bodyexhibiting a textured surface including a plurality of protrudingportions and a plurality of recesses, wherein each protruding portion isseparated from an adjacent protruding portion by a recess of theplurality of recesses. The body is compressed within a delivery vehicleand the delivery vehicle is positioned adjacent an opening of the LAA.The body is discharged from the delivery vehicle into the LAA andexpanded such that the body engages a side wall of the LAA andsubstantially occludes an opening of the LAA.

In accordance with yet another embodiment of the present invention,another method is provided for modifying a left atrial appendage. Themethod includes disposing a mesh bag within the LAA and disposing atleast one self-expanding body within an interior of the mesh bag. Themesh bag is securely closed to retain the at least one self-expandingbody within the bag.

In another one embodiment, the medical device includes a first framemember, a second frame member, a spring member and a tissue in-growthmember. The first and second frame members include a first and secondflat configuration, respectively, and are non-coplanar with each other.The first frame member is configured to anchor within the left atrialappendage (LAA). The spring member is connected between the first andsecond frame members. The tissue in-growth member is attached to thesecond frame member and is configured to cover an opening of the LAA.

In a further embodiment, the medical device includes a frame memberhaving a substantially flat configuration and includes distal anchormembers for anchoring the frame member within the LAA. The medicaldevice also includes a tissue in-growth member that is attached to theframe member and configured to cover an opening of the LAA.

In yet another embodiment, the medical device includes a frame memberhaving an anchoring system that is configured to anchor the frame memberat least partially within the LAA. The medical device also includes atissue in-growth member that is attached to the frame member and isconfigured to prevent potential embolic material from escaping the LAA.

These and other aspects of the present invention will become more fullyapparent from the following description and appended claims, or may belearned by the practice of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing and other advantages of the invention will become apparentupon reading the following detailed description and upon reference tothe drawings in which:

FIGS. 1A and 1B are perspective and side views of a medical deviceaccording to one embodiment of the present invention;

FIG. 1C illustrates an example of an atrial appendage;

FIG. 1D shows the device of FIGS. 1A and 1B disposed in an atrialappendage;

FIGS. 2A, 2B and 2C are side, end and perspective views, respectively,of another medical device according to an embodiment of the presentinvention;

FIG. 3A illustrates a medical device according to another embodiment ofthe present invention;

FIG. 3B shows the medical device of FIG. 3A disposed in an atrialappendage according to an embodiment of the present invention;

FIG. 4 is an end view of a medical device according to an embodiment ofthe present invention;

FIG. 5 is a side view of a medical device disposed in an atrialappendage according to an embodiment of the present invention;

FIGS. 6A and 6B illustrate respective side and end views of a medicaldevice according to another embodiment of the present invention;

FIG. 6C shows the medical device of FIGS. 6A and 6B disposed in anatrial appendage;

FIG. 7 shows another embodiment of a medical device disposed in anatrial appendage;

FIG. 8 shows another embodiment of a medical device disposed in anatrial appendage;

FIG. 9A is an end view of a medical device according to anotherembodiment of the present invention;

FIG. 9B shows the medical device of FIG. 9A disposed in an atrialappendage according to one embodiment of the present invention;

FIGS. 10A and 10B are end and cross-sectional views of a medical deviceaccording to an embodiment of the present invention;

FIG. 10C shows a variation of the embodiment shown in FIGS. 10A and 10B;

FIG. 10D shows the medical devices of FIGS. 10A-10C disposed in anatrial appendage according to another embodiment of the presentinvention;

FIG. 11 is an end view of a medical device according to yet anotherembodiment of the present invention;

FIG. 12 shows a medical device according to another embodiment of thepresent invention disposed in an atrial appendage;

FIGS. 13A through 13E show variations of a medical device according toadditional embodiments of the present invention;

FIG. 14 shows a medical device disposed in an atrial appendage accordingto yet another embodiment of the present invention;

FIG. 15 shows a medical device in the general form of a substantiallyspherical body according to one embodiment of the present invention;

FIGS. 16A-16C show the medical device of FIG. 15 being deployed into anatrial appendage according to an embodiment of the present invention;

FIG. 16D shows the medical device of FIG. 15 disposed in an atrialappendage;

FIGS. 17A and 17B are side and end views of another medical deviceaccording to an embodiment of the present invention;

FIG. 18A shows a delivery mechanism or apparatus for deploying a medicaldevice in accordance with an embodiment of the present invention;

FIG. 18B shows the delivery mechanism of FIG. 18A deploying the medicaldevice of FIG. 15;

FIGS. 19A and 19B are end views of a medical device while in acompressed, pre-delivery state and an expanded, post-delivery stateaccording to an embodiment of the present invention; and

FIGS. 20A-20D show a medical device and a delivery system at variousstages of deployment according to another embodiment of the presentinvention.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS OF THE INVENTION

Referring to FIGS. 1A through 1D, a medical device 100 is shown that maybe used to occlude or modify an opening or cavity such as a left atrialappendage (LAA) 102 (FIGS. 1C and 1D). The medical device 100 includes aframe 104 having a distal anchoring portion or anchor member 106, aspring or biasing member 108 and a proximal cover portion or covermember 110. It is noted that the use of terms such as “distal,”“proximal,” “upper,” and “lower” and other relative terms are used inparticular reference to the drawings and such use is not to be construedas limiting with regard to absolute positions of various componentsdescribed and discussed herein.

The anchor member 106 may be sized and configured to expand outwardagainst a surface of a wall 112 of the LAA 102 so that upper and lowerportions of the anchor member 106 extend to a dimension that is largerthan the LAA opening 114. The anchor member 106 can be formed of, forexample, a shape memory alloy such as Nitinol. Use of such a materialenables the anchor member 106 to be delivered in a collapsed state andthen self-expand upon deployment in the LAA 102. In another embodiment,the anchor member 106 may be configured to be manually expanded upondelivery to and deployment in the LAA 102. In one embodiment, a springor biasing member 115 may be positioned within the anchor member 106 soas to pull opposing distal and proximal sides of the anchor member 106towards one another such the upper and lower portions of the anchormember 106 are placed in, and maintained in, an expanded or extendedposition.

A plurality of tines 116, which may include, for example, posts orbarbs, may be disposed on the anchor member 106. The tines 116 may belocated and configured to “grab” or otherwise engage the LAA wall 112.With such an arrangement, the anchor member 106 is configured to bepositioned and anchored within the LAA 102 to prevent migration of themedical device 100 out of the LAA 102. In one embodiment, the anchormember 106 may be substantially flat and planar. The anchor member 106may also include a tissue in-growth member 118 associated therewith,such as a polymer substrate, or any suitable known member for promotingtissue growth. According to one aspect of the present invention, thetissue in-growth member can be a porous polymer member, such as apolymer based foam or fabric. In one embodiment, fabric may be disposedover the frame of the anchor member 106. In another embodiment a foammember may be disposed on or within the frame of the anchor member 106.

The cover member 110 is connected to the anchor member 106 via thebiasing member 108. The cover member 110 may include a frame 120 sizedand configured to be larger than the opening 114 of the LAA 102. Theframe 120 can be configured to support a tissue in-growth member 122,such as a polymer substrate, or any suitable tissue promoting orenhancing member. Such tissue in-growth member 122 can be a porousmember, such as reticulated foam, fabric or Dacron®, configured to holdblood cells and to promote and induce tissue growth. With the covermember 110 being coupled with the anchor member 106 via the biasingmember 108, the cover member 110 can be configured to be biased againstthe left atrial wall 124 over the opening 114 of the LAA 102 via thebiasing member 108 after the anchor member 106 is appropriatelypositioned and anchored within the LAA 102.

When deployed within the LAA 102, the medical device 100 covers oroccludes the opening 114 of the LAA to seal off the LAA 102 from theleft atria. Thus, if any embolic material exists within the LAA 102, themedical device 100 prevents such from leaving the LAA 102 and enteringback into the left atria. Additionally, the medical device preventsfurther entry of blood into the LAA 102 and, thus, further preventingproduction of embolic material within the LAA.

Referring now to FIGS. 2A through 2C, another medical device 130 isshown which is configured to be anchored within and occlude a cavitysuch as an LAA 102 (FIG. 1C). The medical device 130 may include amulti-planar structure 132 sized and configured to be anchored withinthe LAA 102. The multi-planar structure 132 may be formed of individualplanar structures 132A and 132B arranged to extend in separate planes.Each planar structure 132A and 132B can include a central frame portion134 having a multi-cellular structure with distal anchors 136 extendingtherefrom, the anchors 136 being sized, located and configured to engagethe LAA wall 112 and anchor the medical device 130 therein. Further,each planar structure 132A and 132B may be self-expanding to facilitatethe deployment of the distal anchors 136 and engagement with the LAAwall 112. Such anchoring can be further facilitated with tines 138extending from the distal anchors 136 to grab or more affirmativelyengage the tissue wall 112 of the LAA 102. The multi-planar structure132 provides anchors in multiple planes to ensure the medical device 130is secured within the LAA 102. In addition, each planar structure 132Aand 132B may include proximal anchors 140 extending from the centralframe portion 134. The proximal anchors 140 may be configured to extendaround the outer rim of the opening 114 of the LAA 102 so as to beseated and biased against the left atrial wall 124. The proximal anchors140 may be coupled to a polymer substrate 142 or may be covered by asuitable tissue in-growth member that may cover the opening 114 of theLAA 102 such as has been previously described above.

FIGS. 3A and 3B illustrate another embodiment of a medical device 150configured to engage and be anchored within an LAA 102 (see also FIG.1C) and occlude the opening 114 of the LAA 102. The medical device 150includes a planar structure 152 having distal anchors 154 extending froma multi-cellular central portion 156 that is attached to a cover member158. The cover member 158 may include, for example, a polymer substrate.The medical device 150 is similar to the embodiment described withrespect to FIGS. 2A-2C, except the medical device 150 only employs asingle planar structure 152. The planar structure 152 of the medicaldevice 150 (or the planar structures 132A and 132B of the previouslydescribed medical device 130) may be formed, for example, in a mannersimilar to the planar structures described in U.S. patent applicationSer. No. 11/836,123 filed on Aug. 8, 2007, entitled METHODS, SYSTEMS,AND DEVICES FOR REDUCING THE SIZE OF AN INTERNAL TISSUE OPENING andassigned to the assignee hereof, the disclosure of which is incorporatedby reference herein in its entirety.

The cover member 158 may be sized and configured to be biased or to sitagainst the LAA opening 114. Further, as with other embodiments, thecover member 158 is not limited to a polymer substrate, but may includeany suitable tissue in-growth member known in the art. Additionally,with reference to FIG. 3B, which shows a rotated view of the medicaldevice 150 as compared to that of FIG. 3A, the cover member 158 may bepositioned within the LAA 102 so as to fold distally (as shown in dashedlines) and against the LAA wall 112. In another embodiment multiplecover members 158 may be used with one folded within the LAA 102 andanother covering the opening 114.

FIG. 4 shows an end view of another medical device 160 according to anembodiment of the present invention. The medical device is similar tothat which is described with respect to FIGS. 2A through 2C having aplurality of planar structures 162A, 162B and 162C coupled with a covermember 164. The cover member 164 exhibits a different size and shapethan that of the medical device 130 of FIGS. 2A-2C. Additionally, tocompliment the elongated geometry of the cover member 164, one of theplanar structures 162A is also elongated and multiple planar structures162B and 162C are associated with the elongated planar structure 162A toextend out-of-plane (e.g. orthogonally) with respect to the elongatedplanar structure 162A. With the anchoring system having multiple flat orplanar structures, it can provide additional support and anchoring tothe LAA wall 112 to prevent migration of the device. Additionally, thisconfiguration enables closure of an LAA 102 (FIG. 1C) that, for example,is relatively large or exhibits an elongated opening.

Referring now to FIG. 5, another medical device 170 is shown. Themedical device 170 is generally similar to that which is described withrespect to FIGS. 3A and 3B and includes a planar structure 172 coupledwith a cover member 174. However, rather than using anchors that extenddistally within the LAA 102 (as described with respect to FIGS. 3A and3B), anchors 176 are coupled to the central portion 178 of the planarstructure 172 so as to extend back towards the cover member 174 and intothe flesh of the LAA wall 112.

Referring now to FIGS. 6A through 6C, another embodiment of medicaldevice 190 is shown. In this embodiment, the medical device 190 includesa multi-arm anchor 192 coupled with a cover member 196. As with theother embodiments described herein, the cover member 196 may include asuitable tissue in-growth material to promote or enhance growth oftissue into and over the cover member 196.

The anchor 192 includes a plurality of arms 192A-192D joined at acentral hub 194. Along the length of each arm 192A-192D, tines 96 mayextend therefrom and be oriented so that the medical device 190 issubstantially prevented from migrating from the LAA 102 once it isdisposed therein. The arms 192A-192D may each extend from the centralhub 194 and self-expand when delivered to the LAA 102 in a manner suchthat each arm 192A-192D independently expands and biases against the LAAwall 112 to secure the medical device 112 within the LAA 112. A biasingmember 199 may be coupled between the anchor 192 and the cover member196 so as to bias the cover member 196 against the atrial wall 124 andmore effectively cover or occlude the LAA opening 114.

FIG. 7 illustrates an embodiment of a medical device 200 that includesan anchor 202 similar to that described with respect to FIGS. 6A through6C. The medical device 200 of this embodiment includes a foam or fabric204 disposed over the proximal ends of the anchor 202. In oneembodiment, the foam or fabric 204 may be configured to substantiallyfill or cover the envelope defined by the geometry of the expandedanchor 202. Similar to previously described embodiments, tines 206 maybe associated with the anchor 202 to engage the LAA wall 112.

FIG. 8 illustrates another embodiment of a medical device 210 having ananchor 212 coupled to a cover member 214 via a biasing member 216. Theanchor 212 may include a distal end portion 218 configured to beconnected to the LAA wall 114 such as by tines or barbs 220 or bystitching. Similar to previous embodiments, cover member 214 can,thereby, be biased against the left atrial wall 124 so as to cover theLAA opening 114. Again, the cover member 214 may include an in-growthmaterial, such as a polymer substrate.

Referring now to FIGS. 9A and 9B, a medical device 230 is shown thatincludes a self-expanding frame structure 232 having a plurality ofspokes 234 joined at a common hub 236. The self-expanding feature of theframe structure 232 can assist or substantially ensure that the medicaldevice 230 is secured within the LAA 102 by exerting an appropriateradial force against the LAA walls 114. An in-growth material 238 (onlypartially shown for purposes of clarity), which may include a polymersubstrate such as foam or fabric, may extend around the frame structure232 to promote tissue growth and, thereby, close the opening 114 of theLAA 102. As shown in FIG. 9B, the frame structure 232 may act to closethe LAA 102 on its own accord, or it may be used in conjunction with aseparate cover member 240 (shown in dashed lines) and act as ananchoring device (or as a redundant closure device) associated with sucha cover member 240.

FIGS. 10A through 10D illustrate a medical device 250 having aself-expanding frame structure 252 that expands in a radial direction soas to engage the walls 114 of an LAA 102. The frame structure 252 can besubstantially planar or flat and can be a continuous or unitarystructure. The frame structure 252 may exhibit any of a variety ofgeometric configurations when it is in an expanded state. For example,the frame structure may exhibit a circular geometry as indicated in FIG.10A, or it may exhibit a substantially oval geometry as indicated inFIG. 10C. The frame structure 252 may exhibit any other suitableperipheral shape that enables the frame structure 252 to expand andcause associated tines 254, extending from the periphery of the framestructure 252, to grab or engage the LAA wall 114 as indicated in FIG.10D. A polymer substrate 256 (or any suitable tissue growth promotingmember) may be attached to the frame structure 252. For example, thematerial of such a substrate 256 may wrap around and encase the framestructure 252, it may extend between opposing peripheral sides of theframe structure 252, or it may do both. In another embodiment, themedical device may be devoid of tines such that it relies solely on aradially expanding force of the frame structure 252 to maintain medicaldevice within the LAA 102.

FIG. 11 illustrates another embodiment of a medical device 260 to bedisposed and anchored within an LAA 102 (FIG. 1C). The medical 260 mayinclude a self-expanding frame member 262, that may exhibit a flatconfiguration with a rounded or arcuate periphery when in an expandedstate, with tines 264 configured to anchor within the LAA wall 114. Thetines 264 are curved such that they do not extend directly radiallyoutward from the frame member 262. Such a configuration enables themedical device 260 to engage the LAA wall 114 by rotating the expandedmedical device 260 within the LAA 102 to effectively lodge the tineswithin the LAA wall 114. One advantage of rotating the device to effectanchoring thereof is that the device is anchored without having to pullthe device in the proximal direction to effect such anchoring. Themedical device 260 may further include a polymer substrate 266 or otherin-growth material to act as a cover member and effect tissue growthwhen disposed within the LAA 102. In another embodiment, the framemember 262 could act as an anchor member for a separate cover membersuch as has been described hereinabove.

FIG. 12 illustrates another embodiment of a medical device 270. Themedical device includes a frame member 272 having multiple elongatemembers 272A and 272B that are configured to bypass or cross each otherat an intermediate portion 274 of each elongate member 272A and 272B.The frame member 272 can be self-expanding and, when in the expandedconfiguration, each elongate members 272A and 272B may expand to acurvilinear configuration such that the multiple elongate memberscooperate to collectively exhibit a geometry in the shape of an hourglass. From a common juncture (i.e., the intermediate portion 274 of themultiple elongate members 272A and 272B), there are distally extendingportions 276 and proximally extending portions 278 of the elongatemembers 272A and 272B that form the hour glass configuration. Thedistally extending portions 276 can act as distal anchor portions. Theproximally extending portions 278 can act as proximal anchor portionsand a support structure for a proximal cover portion (not shown in FIG.12). As in the previous embodiments, the frame member 272 can include anin-growth member, such as a polymer substrate, to act as a cover and/orto promote or induce tissue growth.

Referring now to FIGS. 13A through 13E (and continued reference to theLAA shown in FIG. 1C), various embodiments of another medical device 280are shown. As seen in FIGS. 13A through 13C, the medical device 280 mayinclude a frame member 282 formed to exhibit the shape of a helicalcoil. FIG. 13A shows and end view of the medical device 280 while FIG.13B shows a side view of the medical device 13B.

The frame member 282 may be formed from, for example, a shape memberalloy such as Nitinol, such that the frame member 282 may be disposedwithin a catheter 284 or other delivery vehicle in an undeployed (e.g.,a lengthened, uncoiled) state. When deployed from the catheter 284 orother delivery vehicle, the frame member 282 expands to its coiled statesuch as shown FIGS. 13A-13C. When in the expanded, coiled state, theframe member 282 may be sized to engage the LAA wall 112 and apply adesired force to anchor or lodge the medical device 280 within the LAA102. While not expressly shown in FIGS. 12A-13C, the frame member 282may be coupled to a cover member, such as been described with respect tonumerous other embodiments herein, to cover or occlude the LAA opening114.

In another embodiment, and as shown in FIGS. 13D and 13E, the framemember 282 may be coated or encased with a foam or other tissuein-growth material 286. Depending on the thickness of the coating ofsuch material on the frame member 282, and depending on the radius andspacing of the coils of the frame member 282, such a configuration mayact as an occluding member due to the collection or accumulation of thein-growth material on and within the coils of the frame member 282. Inyet other embodiments, the frame member need not be in the configurationof a helical coil. Rather, for example, it may for a substantiallycircular geometry or oval geometry such as are exhibited by theembodiments described with respect to FIGS. 10A-10D. In otherembodiments, the frame member may be a coil which is substantially flator lies within a single plane. Other geometric configurations are alsocontemplated.

FIG. 14 illustrates another embodiment of a medical device 290configured to be disposed within and fill or occlude the LAA 102 (FIG.1C). The medical device 290 includes a foam body 292 that is sized andconfigured such that, when deployed within the LAA 102, the LAA 102expands to a size that is larger than its natural state. After the foambody 292 is disposed within the LAA 102, a stiffener material may thenbe released from a catheter 294 and injected throughout the foam body292 to cause the foam body 292 to become substantially rigid or stiff.The foam body may be anchored within the LAA by virtue of the forcesapplied to the LAA wall 112, by its rigidity, or through a combinationof both properties. Although not shown, the medical device 280 may alsoinclude a cover member to further prevent potential embolic materialfrom migrating from the LAA 102.

Referring now to FIG. 15, another medical device 300 is shown. Themedical device 300 includes a body 302 which may exhibit a substantiallyspherical geometry and have a textured surface. The textured surface mayinclude a plurality of protruding portions 304 (which may exhibit any ofa variety of shapes) separated by recessed portions 306. In oneembodiment of the present invention, the body 302 includes aself-expanding resilient porous material that, when fully expanded,enlarges to a predetermined expanded shape. The body 302 may be formed,for example, of a foam material. For example, the body may be formed apolyurethane material, a polymer foam, or a polyvinyl acetate material,silicon material, or polyester material. Other polymeric materials thatcan be utilized are self-expanding felts. In the case of foam, such foammay be a reticulated foam, typically undergoing a heating process toopen the pours within the foam as known in the art. The foam may also bea non-reticulated foam.

It is also contemplated that the body 302 of the medical device 300, inanother embodiment, can be formed without the plurality of protrudingportions and recessed portions described above. In other words, thesurface of the body 302 can be left relatively smooth or untextured inits substantially natural state of, for example, the foam material.

In one embodiment, the body may be a “solid” geometry meaning that thefoam or other material extends through the body 302. In anotherembodiment, the body 302 may be substantially hollowed out or hollowedat one or more selected portions within the body 302. When hollowed out,the body 302 would be more compact when collapsed and carried by acatheter or other delivery vehicle. While the body 302 may exhibit othergeometries (e.g., cylindrical, ovoid, elongated), the use of a sphericalor substantially spherical geometry (referring to the overall shape anddisregarding the textured surface) enables deployment of the medicaldevice 300 within an LAA 102 (FIG. 1C) with less sensitivity to theapproach angle of the catheter or other delivery vehicle with respect tothe LAA 102. Thus, use of a substantially spherical configurationprovides greater ease of use in installing or deploying the medicaldevice 300. Other configurations may also be employed, such as conical,cylindrical or combinations thereof, which also may include hollowed outportions.

In another embodiment, the foam or other material can include variationswithin portions of the body 302 such that various portions of the bodymay compact smaller than other portions of the body. Such can beemployed, for example, by manipulating the number of pours per squareinch in the material forming the body 302 so that the body exhibits agraded porosity. For example, for a spherical configuration, the centralregion of the foam body may include a different number of pours than theouter regions of the foam body so as to manipulate the compactive andexpansive characteristics of the foam body. Additionally, oralternatively, one-half of the sphere may exhibit one level of porositywhile the other half exhibits a different level of porosity. Similarly,along the length of any other shaped configuration, such as a conical orcylindrical configuration the level of porosity may change.Additionally, such changes in porosity may be gradual, or may berelatively abrupt.

Referring to FIGS. 16A through 16D, deployment of the medical device 300is shown. As seen in FIG. 16A, a catheter 310 or other delivery vehicleis guided to the LAA 102 using techniques that will be appreciated andunderstood by those of ordinary skill in the art. The catheter 310enters the LAA 102 and begins to deploy the body 302 from within thecatheter 310. As seen in FIGS. 16A-16C, as the medical device isdeployed from the catheter 310, it expands (the body 302 being formed ofa self-expanding material) so as to fill or substantially fill the LAA102. In other embodiments, the body 302 may simply fill enough of theLAA 102 to anchor itself within the LAA 102 and to block or occlude theLAA opening 114. FIG. 16D shows the medical device disposed within theLAA 102.

The textured surface of the body 302 may be tailored depending on avariety of factors. For example, the protruding portions 304 may beconfigured to effect increased engagement with the LAA wall 114 (FIG.1C) and help anchor the medical device 300 within the LAA 102.Additionally, the depth, width and frequency of the recessed portions306 of the textured surface may be configured to cooperatively engagewith trabeculations within the LAA 102. Further, the textured surfacemay have portions that are selectively configured for a specificfunction as will be discussed in further detail below.

Referring briefly to FIGS. 17A and 17B, another embodiment of a medicaldevice 320 is shown. The medical device 320 is similar to that which isdescribed with respect to FIG. 15 and includes a body 322 have atextured surface with protruding portions 324 separated by recessedportions 326. The body 322, while exhibiting a generally sphericalgeometry, is truncated on one side to define an opening 328 that exposesthe hollow interior 330 of the body 322. The opening 326 does not impairthe functionality of the medical device to occlude the LAA opening 114(FIG. 1C) so long as the opening 328 is positioned such that it is fullywithin the LAA 102 and not directly exposed to the LAA opening. In otherwords, the opening should be positioned so as to not create acommunication path between the atria and the LAA 102. Such aconfiguration further reduces the overall mass of the body 302 making itsmaller when compacted within a catheter or other delivery mechanism.Additionally, such a configuration may be easier to manufacture whenusing certain manufacturing processes as will be appreciated by those ofordinary skill in the art.

Referring now to FIGS. 18A and 18B, delivery and recapture of themedical device 300 described with respect to FIG. 15 is described. Themedical device 300 is collapsed and retained within a slotted sleeve 340associated with the catheter 310. The slotted sleeve 340 includesmultiple fingers or elongated members 342 having free ends. The catheter310 is guided to the LAA 102 (FIG. 1C) using techniques familiar tothose of ordinary skill in the art. When the catheter 310 is in positionfor delivery of the medical device 300, the slotted sleeve 340 extendslongitudinally out from an opening of the catheter 310. The fingers orelongated members 342 are configured to radially expand (due to selfexpansion, expansion due to the force applied by the medical device 300,or both), and the medical device is released from the slotted sleeve342.

As will be appreciated by those of ordinary skill in the art, it issometimes necessary to recapture the medical device 300 after deploymentfor purposes of repositioning the medical device within the LAA 102. Insuch a case, a tether 346 may be coupled to a plurality of ties 348 thatcircumscribe the body 302 of the medical device. The tether 346 and theweb or cage formed by the ties 348 pull the medical device 300 backwithin the envelope defined by the radially expanded fingers 342 of theslotted sleeve 340. As the tether 346 and slotted sleeve 340 are drawnback in through the opening 344 of the catheter 310, the medical device300 is returned to a collapsed state within the catheter 310 and may beredeployed into the LAA or removed completely from the patient. When thedevice 300 is satisfactorily position with the LAA 102, the tether maybe disconnected from the ties 348.

In one embodiment, such ties 348 may be formed of a shape memory alloy,such as Nitinol, to assist in expansion of the medical device 300 inexpanding when deployed in the LAA. The ties 348 may be disposed withinrecesses 306 of the medical device's textured surface. When deployed inan LAA 102, the ties 348 may remain with the body 302, although they maynot be intended to serve any specific purpose in terms of anchoring themedical device 300 or promoting tissue growth. In another embodiment,instead of using ties 348 for recapture purposes, a mesh bag may bedisposed about the body 302 of the medical device 300 in a mannersimilar to a further embodiment that is described hereinbelow.

In yet another embodiment, the slotted sleeve 340 need not be utilized.Instead, a pusher element (e.g., a rod or other device) may be insertedthrough the body 302 and configured to engage the distal end of the body302. When it is desired to recapture the medical device 300, the pusherelement may push against the distal end of the body while the ties arepulled toward the catheter 310 to effect an elongation (and acorresponding radial contraction) of the body 302. The medical devicemay then be drawn back within the catheter 310.

Referring now to FIGS. 19A and 19B, schematics are shown of a medicaldevice 300 in a collapsed state (i.e., when in a catheter or otherdelivery vehicle), and an expanded state, respectively. Collapse of themedical device 300 may be assisted by ties 348 such as have beendescribed above in terms of retaining the body 302 in a relativelycompact form. When the medical device 300 is in a collapsed state,certain portions of its outer surface are in contact with the deliveryvehicle. These areas are referred to herein as delivery contact surfacesand are generally indicated by reference numeral 350. It may bedesirable to reduce the friction between these delivery contact surfaces350 and the delivery vehicle. Thus, in certain instances, the size andshape of the protrusions 304 may be selectively tailored for suchdelivery contact surfaces 350.

In yet another embodiment, the protrusions 304 in the contact surfaceareas 350 may exhibit similar geometric configurations as the rest ofthe texture surface of the body 302. However, the surface areas not incontact with delivery vehicle (referred to as delivery non-contactsurface indicated by reference numerals 352) may be modified bystiffening the material or further roughening the surface of theprotrusions 304. For example, such delivery non-contact areas may becoated or metalized, such as with graphite, to stiffen the protrusions304 and provide a roughened surface area. These coated areas thenprovide improved engagement of the medical device 300 with the LAA wall114 (FIG. 1C) when deployed in the LAA 102. Such coating ormetallization can also serve another purpose to provide radio opacityfor imaging purposes. Materials that can be used for such coating can betungsten, platinum, gold or titanium or any other materials known in theart to provide radio opacity.

Referring now to FIGS. 20A through 20D, a medical device 360 accordingto another embodiment of the present invention is described. The medicaldevice 360 includes a mesh bag 362 and a plurality of self-expandingbodies 364, such as foam bodies. The mesh bag 362 may be formed, forexample, from nylon, polyester, knitted fiber, or some other appropriatematerial. In another embodiment, the bag 362 may be formed as a moldedsilicone material. As shown in FIG. 20A, the mesh bag 362 is deliveredfrom a catheter 366 or other delivery mechanism into the LAA 102.Individual, self-expanding bodies 364 are then disposed into the meshbag 362 from a separate sleeve or lumen of the catheter 366 as shown inFIGS. 20B and 20C. The expansion of the self-expanding bodies 364stretches the mesh bag 362 such that the medical device 360substantially conformally fills the LAA 102. Once the LAA is filled, themesh bag 362 is tied off or otherwise securely closed to retain theself-expanding bodies 364 within the bag 362 and the LAA 102.

Use of a mesh bag 362 and multiple self-expanding bodies 364 againprovides ease of use for the doctor deploying the medical device due tothe fact that deployment is relatively insensitive to the approach angleof the catheter 366. Additionally, the use of multiple smaller expandingbodies 364 makes it more likely to substantially fill the LAA 102 in agenerally conformal manner.

Various other features may be included in any of the above describedembodiments. For example, radio opaque markers may be associated withany of a variety of components of the described medical devices tofacilitate monitoring of the deployment and positioning of the medicaldevice. Additionally, various materials may be used includingbioresorbant materials for certain components. Further, variouscomponents may be coated to effect a desired biological reaction as willbe appreciated by those of ordinary skill in the art.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description.

What is claimed is:
 1. A medical device for modifying a left atrialappendage (LAA), comprising: a frame member including distal anchormembers for anchoring the frame member within the LAA, the frame memberincluding a unitary, seamless central portion having a plurality ofstruts defining a multi-cellular structure extending between andconfigured to self-expand and directly bias the distal anchor membersagainst a wall in the LAA, the plurality of struts and the distal anchormembers extending in a common plane; and a tissue growth member attachedto the frame member and configured to occlude an opening of the LAA;wherein the distal anchor members comprise first and second distalanchor members extending in a first plane and third and fourth distalanchor members extending in a second plane, the first plane transverseto the second plane.
 2. The medical device of claim 1, wherein thedistal anchor members comprise a first distal anchor portion and asecond distal anchor portion with the central portion extendingtherebetween.
 3. The medical device of claim 1, wherein the distalanchor members comprise tines extending therefrom for engaging the wallin the LAA.
 4. The medical device of claim 1, wherein the frame membercomprises proximal anchor members extending from the central portion. 5.The medical device of claim 4, wherein the tissue growth member isdirectly attached to the proximal anchor members.
 6. The medical deviceof claim 1, wherein the multi-cellular structure of the central portionextends with a substantially flat configuration.
 7. The medical deviceof claim 6, wherein the tissue growth member comprises a polymericsubstrate.
 8. A medical device for modifying a left atrial appendage(LAA), comprising: a frame member including a central portion having aplurality of struts defining a multi-cellular structure and an anchoringsystem, the plurality of struts and the anchoring system extending in acommon plane, the plurality of struts extending between and configuredto self-expand and directly bias the anchor system to anchor the framemember at least partially within the LAA; and a tissue growth memberattached to the frame member; wherein the anchoring system comprises: afirst distal anchor and a second distal anchor, the first distal anchorbeing co-planar with the second distal anchor; and a third distal anchorand a fourth distal anchor, the third distal anchor being co-planar withthe fourth distal anchor, the first distal anchor extending in adiscrete plane relative the third distal anchor.
 9. The medical deviceof claim 8, wherein the multi-cellular structure of the central portionextends with a substantially flat configuration.
 10. The medical deviceof claim 8, wherein the frame member comprises proximal anchor membersextending from the central portion.
 11. The medical device of claim 10,wherein the tissue growth member is attached to the proximal anchormembers.
 12. The medical device of claim 8, wherein the distal anchormembers comprise tines extending therefrom for engaging the wall in theLAA.
 13. The medical device of claim 8, wherein the central portion is aunitary and seamless structure.